PROJECT SUMMARY Oral squamous cell carcinoma (OSCC) remains a challenging clinical problem because of the persisting high rate of local and distant failure. Hypoxia is prevalent in OSCC and often provides a strong selective pressure for the most aggressive and metastatic tumors, which emphasize the need for better understanding of molecular mechanisms and regulators responsible for the acquisition of metastatic potential under hypoxic conditions. We now have data demonstrating that ADP-ribosylation factor 1 (Arf1), a hypoxia-responsive trafficking protein, is required and sufficient to hypoxia-induced OSCC invasion and metastasis. The aberrant overexpression and hyperactivation of Arf1 leads to increased invasion potential upon hypoxia, raising the possibility to develop novel regimens by targeting Arf1 in order to eventually increase cure rate in OSCC. Our overarching goal is to improve the survival of patients with OSCC by revealing the functional consequences of Arf1 dysfunction under hypoxia and understanding the underlying mechanisms. There are two aims in the proposal to test our hypothesis. Aim 1 is to dissect the cooperatively transcriptional and epigenetic regulation in hypoxia-induced Arf1 upregulation. Aim 2 is to Illustrate the molecular mechanism and the functional consequences of hypoxia-induced Arf1 hyperactivation. These pilot studies will provide a solid rationale for a more comprehensive investigation into the regulation and role of Arf1 in hypoxic OSCC for which future R01 mechanism support will be sought. Overall, our studies will gain mechanistic insight into hypoxia-induced OSCC metastasis by exploring Arf1 as a novel druggable target for hypoxic tumors, and build a foundation for Arf1-targeted anticancer therapeutic modality. This project would directly impact the future development of prognostic variables and treatment strategies for OSCC, especially for those tumors in hypoxic microenvironment.